The present invention is related to Japanese patent application No. Hei. 11-208266, filed Jul. 22, 1999; the contents of which are incorporated herein by reference.
The present invention relates to a vehicle-drive system, and more particularly, to a vehicle-drive system, which recovers inertial energy from a vehicle.
In conventional vehicle-drive systems, torque from an internal-combustion engine is transferred to a vehicle drive shaft through a main clutch, an input shaft and a transmission. A starter, a generator motor and accessories for the vehicle-operating system are connected to a crank shaft through a belt drive system. However, when the vehicle is no longer accelerating, the inertial energy of the vehicle supplies energy from the wheels to the engine, and then to the vehicle accessories. However, in this system, when the generator and accessories are driven by inertial power of the vehicle, the inertial power of the vehicle cannot effectively be recovered due to friction loss from the internal-combustion engine, resulting in little fuel-cost savings. Moreover, when the vehicle is braked, the vehicle looses even more inertial energy due to the braking operation. The present invention was developed in light of these drawbacks.
It is therefore an object of the present invention to provide a vehicle-drive system, which drastically improves recovery of inertial power of a vehicle lost due to braking.
It is a further object of the present invention to provide the above described system while avoiding structural complication thereof.
It is yet another object of the present invention to aid the internal combustion engine when the engine is being started or is operating under a large load.
The present invention achieves the above-described objects by providing a device that transfers torque from an internal-combustion engine of a vehicle-drive system to a transmission through a main clutch. A dynamo-electric-machine mechanism is connected to an input shaft of the transmission through an assistant clutch. Accessories are connected to the dynamo-electric-machine mechanism. Different modes of operation are then achieved by connecting and disconnecting the main and assistant clutch.
In another aspect of the present invention, a torque converter with a lock mechanism is used. The torque converter is disposed between the input shaft of the transmission, the main clutch and the assistant clutch. In this aspect, both the clutches can be attached to an input shaft of the torque converter. However, where this torque converter is used, it is preferable that the torque converter with a lock mechanism is employed for brake operation and is locked during braking of the vehicle.
In a further aspect of the present invention, the accessories are connected to the input shaft of the transmission through the assistant clutch.
In another aspect of the present invention, the dynamo-electric-machine mechanism drives the accessories with the assistant clutch disconnected when the internal-combustion engine and the vehicle are not operating. Here, when the internal-combustion engine is started, the dynamo-electric-machine mechanism drives the internal-combustion engine through both clutches while both are connected. The vehicle recovers inertial power when it is braked through the assistant clutch, while the main clutch is disconnected. When the internal-combustion engine is started, the vehicle is driven by the internal-combustion engine through both the clutches. Therefore, inertial power from the vehicle is recovered by the dynamo-electric-machine mechanism instead of being lost as friction in the internal-combustion engine. When the internal-combustion engine is started, the transmission is shifted to neutral or park. Accordingly, the output shaft of the transmission is not driven by the dynamo-electric-machine mechanism.
When the internal-combustion engine is operated, the dynamo-electric-machine mechanism is driven by the internal-combustion engine through both the clutches. However, when operating, the internal-combustion engine supplies power through the transmission. When idling, the internal-combustion engine supplies torque to the dynamo-electric-machine mechanism and the accessories while preventing torque from being transferred through the transmission. This is accomplished by shifting the transmission to the neutral position or the parking position or by depressing a brake pedal with the torque converter being added to the transmission.
In another aspect of the invention, the accessories are connected to the dynamo-electric-machine mechanism not through the clutch. The accessories recover inertial power from the vehicle through the assistant clutch with the main clutch disconnected. The accessories are driven together with the dynamo-electric-machine mechanism by the internal-combustion engine through both the clutches when the internal-combustion engine is operated.
In another aspect of the invention, the dynamo-electric-machine mechanism operates electrically and assists the internal-combustion engine in supplying torque for running. This assisted torque is supplied through the assist clutch, connected when the engine undergoes a large running load, while operating. Therefore, larger torque can be obtained.
In another aspect of the invention, both clutches are connected to make the dynamo-electric-machine mechanism generate electricity during major brake operations of the vehicle wherein the vehicle is decelerated quickly. The vehicle can be braked due to both friction loss of the internal-combustion engine and recovery-electric power of the dynamo-electric-machine mechanism.
The accessories can be connected directly to the dynamo-electric-machine mechanism through the torque-transfer mechanism, or to the input shaft of the transmission through the torque-transfer mechanism. Further, the accessories can be connected to the torque-transfer mechanism as described above through an added clutch.
In another aspect of the invention, an undulating lever for the main clutch and an undulating lever for the assistant clutch are disposed around the input shaft of the transmission, with their undulating spaces being overlapped in axial directions thereof. The undulating lever for the main clutch is a portion of an impelling mechanism for connecting or disconnecting the main clutch. The undulating lever for the assistant clutch is a portion of an impelling mechanism for connecting or disconnecting the assistant clutch. Therefore, the input shaft of the transmission (including a shaft of a disk connected to the input shaft of the transmission) can be shortened, thereby making the structure of the system more compact. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.